A function expansion unit such as a port replicator or a docking station for a notebook computer is widely known. The function expansion unit receives the notebook computer on an external surface. A connector arranged on the surface of the function expansion unit is connected to a connector of the notebook computer. A variety of peripheral devices are connected to the notebook computer using the function expansion unit, as described in Japanese Unexamined Patent Application Publication No. 1993-73174, Japanese Unexamined Patent Application Publication No. 2001-5573, Japanese Unexamined Patent Application Publication No. 2002-16386, and Japanese Unexamined Patent Application Publication No. 2000-216574.